394 ON GENERATION. 



already prepared, it is carried as nourishment for the chick ; 

 still it is certain that the greater portion of the yelk remains 

 after the disappearance of the albumen; that it is laid up in the 

 abdomen of the chick when excluded, and, attracted or absorbed 

 by the branches of the vena portse, that it is finally carried to 

 the liver. 



It is manifest, therefore, that the chick when hatched, is 

 nourished by the yelk in the first period of its independent 

 existence. And as within the egg the embryo was nourished 

 partly by the albumen, partly by the vitellus, but principally 

 by the albumen, which is both present in larger quantity, and 

 is more speedily consumed, so when the chick is hatched, and 

 when all the nourishment that is taken must pass through the 

 liver to undergo ulterior preparation, is it nourished partly by 

 the vitellus and partly by chyle absorbed from the intestines, 

 but principally by chyle, which the host of subdivisions of the 

 mesenteric vessels seize upon, whilst there is but a single vessel 

 from the porta distributed to the vitellus, and by and by but 

 little of it remains. Nature, therefore, acts as does the nurse, 

 who gradually habituates her infant to the food which is to 

 take the place of her failing supply of milk, The pullet is 

 thus gradually brought from food of more easy to food of more 

 difficult digestion, from yelk to chyle. 



Wherefore there is every reason for what we perceive in 

 connexion with the course of the veins in the egg. When the 

 embryo first begins to be formed, they are distributed to the 

 colliquament only, where the blood finds suitable nutriment 

 and matter for the formation of the 'body ; but by and by they 

 extend into the thinner albumen, whence the chick, whilst it is 

 yet in the state of gelatine or mucor, and resembles a maggot in 

 form, derives its increase ; the branches next extend into the 

 thicker albumen, and then into the vitellus, that they may also 

 contribute to the support of the foetus, which, having at length 

 arrived at maturity and been extruded, still preserves a portion 

 of the yelk (or milk) within its abdomen, whereby it is main- 

 tained in part, in part by food selected and prepared for it by 

 the mother, until it is able to look out for and to digest its own 

 aliment. Thus does nature most wisely provide food through 

 the whole round of generation, suited to the various strength 

 of the digestive faculty in the future being. In the first period 



